Recommendations on minimum requirements for the seismic design and detailing of suspended grid systems

Abstract

KRTA Limited were commissioned by the Earthquake and War Damage Commission (EQC) to conduct a research project involving a worldwide literature search to gather information on seismic design of suspended ceilings. The project was titled “Recommendations on minimum requirements for the seismic design and detailing of suspended ceiling grid systems”. The research was to target four major areas:

1. To determine the effectiveness, necessity and adequacy of current New Zealand regulations (which appear to be based on dated information);
2. To make particular reference to clipping of ceiling tiles, effects of diaphragm action, displacement and its limitations, and the effects of bracing and influence of partitions;
3. To present the results of the above research in a manner that would assist designers and specifiers to define the structural aspects of the system where such research is conclusive, and
4. To make recommendations to the Earthquake and War Damage Commission on plausible means of implementing suggested modifications to current practice and building controls and/or suggesting what further research will be required. The international literature search addressed 109 individuals and organisations in 15 different countries. Having received replies from many of these countries it has been possible to extend the scope of the report to include comparisons of codes and recommendations of both governmental and non-governmental organisations.

The report is primarily written to apply to suspended grid ceiling systems using inverted ‘T’ rails with lay-in panels. However, many of the problems and solutions discussed are equally applicable to other forms of suspended ceilings.